Generally, in order to manufacture a semiconductor device, various heat treatments such as a film forming process, a pattern etching process, an oxidation diffusion process, a quality modification (reforming) process, and an annealing process are repeatedly performed onto a semiconductor wafer. As semiconductor devices have been developed to have high density, multi-layers, and high integration, requirements thereof have become stricter every year. Further, it is demanded to improve uniformity in the surface of the wafer, to improve a film property and to shorten a required time when performing these various heat treatments.
By way of example, the annealing process or the quality modification (reforming) process has been generally performed onto a surface of the semiconductor wafer by a processing apparatus including a heating lamp or a heater. In the processing apparatus, the semiconductor wafer is heated in an atmosphere of a processing gas such as an inert gas, and the annealing process or the quality modification (reforming) process is performed onto the surface of the semiconductor wafer.
In recent years, when the quality modification (reforming) process or the annealing process for activating dopants is performed, there has been suggested a microwave irradiation apparatus using microwave (see Patent Documents 1 and 2). This is because a thin active layer can be formed while suppressing diffusion of impurities and lattice defects can be recovered.    Patent Document 1: Published Japanese Translation of PCT Patent Application No. 2009-516375    Patent Document 2: Japanese Patent Laid-open Publication No. 2010-129790
As described above, by using the microwave, it is possible to efficiently perform various processes in a short time. When various processes are performed by the above-described microwave irradiation apparatus, it is very important to control a temperature of a semiconductor wafer as a target object. However, a conventional microwave irradiation apparatus cannot sufficiently control the temperature of the wafer. Further, the temperature of the wafer may be controlled by controlling an input power of the microwave. However, in some processes, the power of the microwave and the temperature of the wafer need to be controlled independently from each other, but the conventional microwave irradiation apparatus cannot meet these needs. For this reason, this problem needs to be solved as soon as possible. Further, in other processes, the wafer heated by the microwave needs to be efficiently cooled while the microwave is efficiently irradiated to the wafer.